An upper limit to the masses of stars

Figer, Donald F.

doi:10.1038/nature03293

Cited by 321 publications

(285 citation statements)

References 27 publications

Supporting

Mentioning

256

Contrasting

Unclassified

Order By: Relevance

“…However, stars with larger masses are expected to form in more massive clusters (Oey & Clarke 2005;Weidner & Kroupa 2006). Thus in the framework of this numerical investigation the upper mass limit has been set to the current accepted fundamental upper mass limit, m max = 150 M (Figer 2005;Oey & Clarke 2005;Koen 2006;Weidner & Kroupa 2006;Maíz Apellániz et al 2007;Zinnecker & Yorke 2007).…”

Section: Methodsmentioning

confidence: 99%

Stellar interactions in dense and sparse star clusters

Olczak

Pfalzner

Eckart

2010

A&A

View full text Add to dashboard Cite

Context. Stellar encounters potentially affect the evolution of the protoplanetary discs in the Orion Nebula Cluster (ONC). However, the role of encounters in other cluster environments is less known. Aims. We investigate the effect of the encounter-induced disc-mass loss in different cluster environments. Methods. Starting from an ONC-like cluster we vary the cluster size and density to determine the correlation of collision time scale and disc-mass loss. We use the nbody6++ code to model the dynamics of these clusters and analyze the disc-mass loss due to encounters. Results. We find that the encounter rate depends strongly on the cluster density but remains rather unaffected by the size of the stellar population. This dependency translates directly into the effect on the encounter-induced disc-mass loss. The essential outcome of the simulations are: i) Even in clusters four times sparser than the ONC the effect of encounters is still apparent. ii) The density of the ONC itself marks a threshold: in less dense and less massive clusters it is the massive stars that dominate the encounter-induced disc-mass loss whereas in denser and more massive clusters the low-mass stars play the major role for the disc mass removal. Conclusions. It seems that in the central regions of young dense star clusters -the common sites of star formation -stellar encounters do affect the evolution of the protoplanetary discs. With higher cluster density low-mass stars become more heavily involved in this process. This finding allows for the extrapolation towards extreme stellar systems: in case of the Arches cluster one would expect stellar encounters to destroy the discs of most of the low-and high-mass stars in several hundred thousand years, whereas intermediate mass stars are able to retain to some extant their discs even under these harsh environmental conditions.

show abstract

Section: Methodsmentioning

confidence: 99%

Stellar interactions in dense and sparse star clusters

Olczak

Pfalzner

Eckart

2010

A&A

View full text Add to dashboard Cite

show abstract

“…Here, the variables are the minimum and maximum masses possible in the star-formation processes and the IMF slopes; many values around those suggested by Kennicut were tested. The minimal mass was set to 0.06 solar masses; the upper limit for stellar masses was set to 120 solar masses, a conservative approach to the value suggested by Figer (2005). The generation of masses m 1 and m 2 starts with the equation…”

Section: Simulations From Initial Mass Functionsmentioning

confidence: 99%

The mass ratio and initial mass functions in spectroscopic binaries

Ducati

Penteado

Turcati

2010

A&A

View full text Add to dashboard Cite

Context. Spectroscopic binaries are important in studies of binary star-formation, since original information linked to the forming stars, such as the mass ratio, can be kept in the system and observationally retrieved. Aims. We aim to derive the more probable mass ratio distributions, to test a possible Initial Mass Functions acting on the formation of spectroscopic binaries, and to derive the value of q 0 , the minimal mass ratio for which both binary components are simultaneously in the main sequence. Methods. The sample has 249 systems, selected from the Ninth Catalogue of Spectroscopic Binaries, with selection criteria that include only those systems with periods longer than four days and magnitudes brighter than m V = 7.0, and main-sequence primaries, to avoid mass exchange. Monte Carlo simulations of observational parameters were performed. We performed simulations by comparing an observational quantity, Y obs , equal to f (m)/m 1 , where f (m) is the mass function, to theoretical Y th , which is a function of the system inclination (assumed to be random), and of the mass ratio q = m 2 /m 1 . We considered a minimal mass ratio q 0 , which is the limiting condition, to ensure that both components are simultaneously on main sequence, avoiding evolutionary effects leading to mass exchange and loss of information on the original masses. Calculations were done using several q 0 values. The form of the distribution of mass ratios was studied by simulations of Y, involving several functions, with slopes which are increasing, decreasing, constant, or bimodal. Other simulations were done by the generation of stars following several initial mass function laws. We combined pairs of stars generated from different IMFs, assuming that binaries arise from the pairing of stars simultaneously formed. In this case, several values of q 0 were also used in the input equations. Results. Our results indicate that decreasing q distributions match better with observations and also that a unique IMF gives better fits to observations than a composite IMF, with a slope around 1.4, rather than the widely used 2.35 slope. Values of q 0 tend to be lower than what is suggested by previous studies, which point to q 0 around 0.2; all simulations suggest that q 0 values as low as 0.08 produce the best fits to observations.

show abstract

“…While the upper limit to the masses of stars is thought to be ∼150 M (Figer 2005;Oey & Clarke 2005), or as recently proposed, to be ∼300 M (Crowther et al 2010;Banerjee et al 2012), the observed masses of carbon-rich Wolf-Rayet stars, the predicted endpoints of their evolution (see Georgy et al 2012), do not exceed 20 M (see review by Crowther 2007). Therefore, one or more mechanisms must cause these stars to shed very large amounts of mass in a very short time (e.g.…”

Section: Introductionmentioning

confidence: 99%

Identification of red supergiants in nearby galaxies with mid-IR photometry

Britavskiy

Bonanos

Mehner

et al. 2014

A&A

View full text Add to dashboard Cite

Context. The role of episodic mass loss in massive-star evolution is one of the most important open questions of current stellar evolution theory. Episodic mass loss produces dust and therefore causes evolved massive stars to be very luminous in the mid-infrared and dim at optical wavelengths. Aims. We aim to increase the number of investigated luminous mid-IR sources to shed light on the late stages of these objects. To achieve this we employed mid-IR selection criteria to identity dusty evolved massive stars in two nearby galaxies. Methods. The method is based on mid-IR colors, using 3.6 μm and 4.5 μm photometry from archival Spitzer Space Telescope images of nearby galaxies and J-band photometry from 2MASS. We applied our criteria to two nearby star-forming dwarf irregular galaxies, Sextans A and IC 1613, selecting eight targets, which we followed-up with spectroscopy. Results. Our spectral classification and analysis yielded the discovery of two M-type supergiants in IC 1613, three K-type supergiants and one candidate F-type giant in Sextans A, and two foreground M giants. We show that the proposed criteria provide an independent way for identifying dusty evolved massive stars that can be extended to all nearby galaxies with available Spitzer/IRAC images at 3.6 μm and 4.5 μm.

show abstract

An upper limit to the masses of stars

Cited by 321 publications

References 27 publications

Stellar interactions in dense and sparse star clusters

Stellar interactions in dense and sparse star clusters

The mass ratio and initial mass functions in spectroscopic binaries

Identification of red supergiants in nearby galaxies with mid-IR photometry

Contact Info

Product

Resources

About